Electronic component, electric device including the same

ABSTRACT

Provided is an electronic device including a display panel including a base substrate, pixels, a first insulation layer, and panel pads spaced along a first direction from pixels and each arranged along a second direction crossing the first direction, a circuit board disposed on the display panel and connected to panel pads, and an adhesive interconnect layer disposed between the display panel and the circuit board and electrically connecting the display panel and the circuit board. The circuit board includes a flexible substrate including a top surface facing the base substrate, output pads disposed on the flexible substrate and connected to panel pads, each obliquely extending in the first and second directions and arranged along the second direction, an alignment pad spaced along the second direction from output pads, and a stress relaxation pad disposed between output pads and alignment pads and electrically insulated from panel pads.

CROSS-REFERENCE TO RELATED APPLICATIONS

This U.S. non-provisional patent application claims priority under 35U.S.C. § 119 of Korean Patent Application No. 10-2017-0106276, filed onAug. 22, 2017, the entire contents of which are hereby incorporated byreference.

BACKGROUND

The present disclosure herein relates to an electronic component and anelectronic device including the same, and more particularly, to anelectronic component having improved reliability in a manufacturingprocess and an electronic device including the electronic component.

In general, an electronic device includes two or more electroniccomponents. For example, electronic device such as a mobile phone, alaptop computer and a television includes an electro-optical panelgenerating an image, a main wiring substrate, and a flexible wiringsubstrate.

Two electronic components are electrically connected through theconnection of pads. The pad portions of the two electronic componentsare bonded through an alignment step, and may be bonded by using athermo-compression bonding tool and the like.

The pad portions of the two electronic components may have a sizedifferent from a design size, due to a manufacturing error. In addition,the two electronic components may be shrunk or expanded due to the heatgenerated in the bonding process. Further, delamination and the like mayoccur due to the difference in resilience between electronic componentsafter the bonding process. The reliability in electrical connection ofthe electronic components is lowered for the same reason as describedabove.

SUMMARY

Therefore, the present disclosure is directed to providing an electroniccomponent in which the reliability of electrical connection is improved,and an electronic device including the electronic component.

An embodiment of the inventive concept provides an electronic deviceincluding: a display panel including a base substrate, a plurality ofpixels disposed on the base substrate, a first insulation layer disposedon the base substrate and including an organic material, and a pluralityof panel pads, at least a portion of the plurality of panel pads beingpartially exposed by the first insulation layer, the plurality of panelpads being spaced apart in a first direction from the pixels, and eachof the plurality of panel pads being arranged along a second directioncrossing the first direction; a circuit board disposed on the displaypanel and connected to the plurality of panel pads; and an adhesiveinterconnect layer disposed between the display panel and the circuitboard and electrically connecting the display panel and the circuitboard.

In an embodiment, the circuit board may include a flexible substratehaving a top surface facing the base substrate; a plurality of outputpads which are disposed on the flexible substrate and connected to theplurality of panel pads, each of which extends obliquely with respect tothe first direction and the second direction, and which are arrangedalong the second direction; an alignment pad spaced apart along thesecond direction from the output pads; and a stress relaxation paddisposed between the output pads and the alignment pad, and electricallyinsulated from the plurality of panel pads.

In an embodiment, the output pads may overlap the plurality of panelpads, and the stress relaxation pad may not overlap the plurality ofpanel pads in a plan view.

In an embodiment, the adhesive interconnect layer may be in contact withthe first insulation layer in an area in which, in a plan view, theadhesive interconnect layer overlap the stress relaxation pad in a planview.

In an embodiment, the adhesive interconnect layer may include anadhesive layer, and a plurality of conductive particles dispersed in theadhesive layer, the adhesive layer and the first insulation layer beingin contact with each other in an area overlapping the stress relaxationpad.

In an embodiment, the electronic device may further include a secondinsulation layer disposed between the first insulation layer and thebase substrate, wherein the adhesive force between the first insulationlayer and the adhesive layer is greater than the adhesive force betweenthe first insulation layer and the second insulation layer.

In an embodiment, the stress relaxation pad may include a plurality ofsub-pads which are arranged apart from each other along the seconddirection.

In an embodiment, the sub-pads may extend in a direction parallel to theoutput pads.

In an embodiment, the output pads may have predetermined extensionangles with respect to the first direction, and at least two pads of theoutput pads may have different extension angles.

In an embodiment, the sub-pads may extend in a direction parallel to anoutput pad closest to the sub-pads among the output pads.

In an embodiment, the sub-pads may extend in a direction crossing theoutput pads.

In an embodiment, the stress relaxation pad may be disposed on the samelayer as the output pads, and may include the same material as theoutput pads.

In an embodiment, the length in the first direction of the stressrelaxation pad may be greater than or equal to the length in the firstdirection of the alignment pad, and may be less than or equal to thelengths in the first direction of the output pads.

In an embodiment, the display panel may further include an additionalalignment pad disposed on the base substrate and spaced apart from thealignment pad in second direction, wherein the stress relaxation pad maybe spaced apart from the alignment pad, the output pad, and theadditional alignment pad.

In an embodiment, the display panel may further include a window padspaced apart from the plurality of panel pads and overlapping the stressrelaxation pad and a portion of the first insulation layer overlappingthe widow pad may be removed.

In an embodiment, each of the pixels may include a thin film transistordisposed on base substrate and a pixel electrode connected to the thinfilm transistor, the first insulation layer may be disposed between thethin film transistor and the pixel electrode, and the pixel electrodecontacts the thin film transistor through a contact hole formed in thefirst insulation layer.

In an embodiment of the inventive concept, an electronic componentincludes a flexible substrate including one side extending along a firstdirection; an electronic element disposed on the flexible substrate; aplurality of output pads disposed adjacent to the one side and spacedapart from the electronic element in a second direction crossing thefirst direction, each of the plurality of output pads being spaced apartfrom each other along the first direction and extending obliquely withrespect to each of the first direction and the second direction; analignment pad spaced apart in the first direction from the output pads;and a stress relaxation pad disposed between the output pads and thealignment pad, and electrically insulated from the output pads.

In an embodiment, the stress relaxation pad may include a plurality ofsub-pads extending obliquely with respect to each of the first directionand the second direction, and the plurality of sub-pads are spaced apartfrom the output pads and the alignment pad in a plan view.

In an embodiment, the sub-pads may be parallel to at least any one ofthe output pads.

In an embodiment, the length in the second direction of the stressrelaxation pad may be greater than or equal to the length of thealignment pad in the second direction, and is less than or equal to thelengths of the pads in the second direction.

In an embodiment, the stress relaxation pad may be disposed in the samelayer as the output pads, and may include the same material as theoutput pads.

BRIEF DESCRIPTION OF THE FIGURES

The accompanying drawings are included to provide a furtherunderstanding of the inventive concept, and are incorporated in andconstitute some of this specification. The drawings illustrate exemplaryembodiments of the inventive concept and, together with the description,serve to explain principles of the inventive concept. In the drawings:

FIG. 1 is a plan view illustrating a part of the electronic deviceaccording to an embodiment of the inventive concept;

FIG. 2 is a cross-sectional view taken along line I-I′ illustrated inFIG. 1 ;

FIG. 3A and FIG. 3B are a cross-sectional view and a plan viewillustrating the configuration of the part illustrated in FIG. 1 ,respectively;

FIG. 4 is a plan view in which a part of the electronic deviceillustrated in FIG. 1 is separated;

FIG. 5A and FIG. 5B are plan views in which some of elements illustratedin FIG. 4 are enlarged;

FIG. 5C is a plan view in which the elements illustrated in FIG. 4 arecoupled;

FIG. 6A is a cross-sectional view in which a part of the electronicdevice according to an embodiment of the inventive concept is separated;

FIG. 6B is a cross-sectional view taken along line II-II′ illustratedFIG. 5C;

FIG. 6C is a cross-sectional view illustrating a part of the electronicdevice according to an embodiment of the inventive concept;

FIG. 7A and FIG. 7B are cross-sectional views of a part of an electronicdevice according to a comparative example;

FIG. 8A illustrates a first alignment state of an electronic deviceaccording to an embodiment of the inventive concept;

FIG. 8B illustrates a second alignment state of an electronic deviceillustrated in FIG. 8A;

FIG. 9A illustrates a third alignment state of an electronic deviceaccording to a comparative example;

FIG. 9B illustrates a fourth alignment state of an electronic deviceaccording to a comparative example;

FIG. 10 is a plan view illustrating output pads according to anembodiment of the inventive concept;

FIG. 11A is a plan view in which a part of the electronic deviceaccording to an embodiment of the inventive concept is separated;

FIG. 11B is a plan view illustrating a part of the electronic deviceaccording to an embodiment of the inventive concept;

FIG. 11C is a cross-sectional view taken along line III-III′ illustratedin FIG. 11B;

FIG. 12 is a plan view illustrating a part of the electronic deviceaccording to an embodiment of the inventive concept;

FIG. 13A is a cross-sectional view taken along line IV-IV′ illustratedin FIG. 12 ; and

FIG. 13B is a cross-sectional view illustrating a part of the electronicdevice according to an embodiment of the inventive concept.

DETAILED DESCRIPTION

Hereinafter, an electronic device according to an embodiment of theinventive concept will be described in detail with reference to theaccompanying drawings. Meanwhile, in describing a direction herein, onedirection and opposite direction thereto are described as the samedirection.

FIG. 1 is a plan view illustrating a part of the electronic deviceaccording to an embodiment of the inventive concept. FIG. 2 is across-sectional view taken along line I-I′ illustrated in FIG. 1 . FIG.3A and FIG. 3B are a cross-sectional view and a plan view illustratingthe configuration of the part illustrated in FIG. 1 , respectively.Hereinafter, an electronic device 100 according to an embodiment of theinventive concept will be described with reference to FIG. 1 to FIG. 3B.

An electronic device 100 is driven in response to an electrical signal.The electronic device 100 may include various embodiments. For example,the electronic device 100 may include at least any one among a displaydevice for displaying an image, and an input sensing device for sensinginputs, such as touch, pressure, light and heat, applied from theoutside. In the present embodiment, the electronic device 100 isexemplarily described as a display device.

The electronic device 100 may include a display panel 110, a flexiblecircuit board 120, and a main circuit board 130. The display panel 110,the flexible circuit board 120, and the main circuit board 130 areelectrically connected.

The display panel 110 may include a display area DA, a peripheral areaBA, and a pad area PA in a plan view.

The display area DA may be an area in which an image is displayed. Inthe display area DA, a plurality of pixels PX for realizing an image maybe disposed. Pixels PX may be arranged in a matrix form along a firstdirection A1 and a second direction A2. The display panel 110 controlspixels PX to display various images.

Each of the pixels PX may include a display element and a drivingelement. The display element may include elements according to variousexamples. For example, the display element may be at least any one amonga liquid crystal element, an organic light emitting element, anelectrophoretic element, and an electrowetting element. However, theabove-described elements are merely exemplarily described, and thedisplay element may include elements according to various examples aslong as an image may be realized according to an electrical signal.Thus, the display element is not limited to an element according to anyone example.

The driving element controls driving of each of the display elements ineach of the pixels PX. The driving element may include a thin filmtransistor. The display panel 110 according to an embodiment of theinventive concept may be driven through an active method by which thepixels PX may be each independently controlled.

The peripheral area BA is adjacent to the display area DA. In theperipheral area BA, signal lines connected to the pixels PX may bedisposed. In the present embodiment, the peripheral area BA may have aframe shape surrounding the display area DA. However, the shape of theperipheral area BA is merely exemplarily illustrated, and the peripheralarea BA may thus have various shapes as long as being adjacent to thedisplay area DA. Therefore, the shape of the peripheral area BA is notlimited to a shape according to any one example.

The pad area PA may be adjacent to the peripheral area BA. The pad areaPA may be an area coupled with the flexible circuit board 120. Althoughnot illustrated, a plurality of pads (not illustrated) for beingelectrically connected to the flexible circuit board 120 may be disposedin the pad area PA. The display panel 110 is electrically coupled toexternal electronic components such as the flexible circuit board 120and the main circuit board 130 through the pad area PA.

The display panel 110 may include, in a cross sectional view, a basesubstrate 112, a display element layer 114, and an encapsulation layer116 laminated along a third direction (A3).

The base substrate 112 may be a base layer on which the display elementlayer 114 is formed. The base substrate 112 may be a single layer or mayinclude a plurality of insulation layers. The base substrate 112 may beat least any one among a glass substrate, a plastic substrate, a film,and a laminate including a plurality of organic films and/or inorganicfilms. The base substrate 112 is not limited to one according to any oneexample.

Although not illustrated, a driving element of the pixel PX, a signalline and the like are disposed on the base substrate 112. Accordingly, alaminated structure in which a plurality of conductive layers and aplurality of organic films and/or inorganic films are laminated aredisposed on the base substrate 112.

The display element layer 114 is disposed on the base substrate 112. Thedisplay element layer 114 is electrically connected with the drivingelement and the signal line on the base substrate 112. The displayelement layer 114 includes display elements among the pixels PXdescribed above. For example, when the display panel 110 is an organiclight emitting display panel, the display element layer 114 may includean organic light emitting layer. The display area DA may correspond toan area in which the display element layer 114 is disposed.

The encapsulation layer 116 is disposed on the display element layer 114to cover the display element layer 114. The encapsulation layer 116protects the display element layer 114. Although not illustrated, theencapsulation layer 116 may cover even the side of the display elementlayer 114. In addition, the encapsulation layer 116 may not be includedor may be replaced with another display substrate, according to the typeof the display panel 110.

The flexible circuit board 120 is disposed on the pad area PA of thedisplay panel 110 to connect the main circuit board 130 and the displaypanel 110. The flexible circuit board 120 is disposed on one side of thedisplay panel 110 extending along the second direction A2.

The flexible circuit board 120 may be provided in plurality and arrangedalong the second direction A2. However, such arrangement is merelyexemplarily illustrated, and the flexible circuit board 120 may beprovided as a single component. Thus, the flexible circuit board 120 isnot limited to one according to any one example.

The flexible circuit board 120 includes a flexible wiring substrate 122and a driving circuit 125 disposed on the flexible wiring substrate 122.The flexible wiring substrate 122 and the driving circuit 125 will bedescribed in more detail with reference to FIG. 3A and FIG. 3B.

The flexible wiring substrate 122 includes a flexible substrate 123, anda plurality of pads, and a plurality of wirings SL-120 may be disposedon the flexible wiring substrate 122.

The flexible substrate 123 may have a rectangular shape in a plan view.For example, the flexible substrate 123 includes a first side S1 and asecond side S2 each of which extends along the second direction A2 andwhich are opposites to each other in the first direction A1, and a thirdside S3 and a fourth side S4 each of which extends along the firstdirection A1 and which are opposites to each other in the seconddirection A2. However, this shape is merely exemplarily illustrated, andthe flexible substrate 123 may have various shapes, and thus have aplurality of sides.

The pads and the wirings SL-120 are disposed on the flexible substrate123. The flexible substrate 123 may include poly imide (PI).

The pads include connection pads CPD, input pads IPD-120, output padsOPD-120, alignment pads APD-120, and at least one stress relaxation padSPD. In FIG. 3B, the connection pads CPD are disposed between thedriving circuit 125 and the flexible substrate 123.

The connection pads CPD are connected to connection terminals (notillustrated) of the driving circuit 125. In this embodiment, theconnection pads CPD are disposed along both sides of the driving circuit125, but such alignment is merely exemplarily illustrated. Thus, theconnection pads CPD may be randomly arranged corresponding to theconnection terminals of the driving circuit 125.

The input pads IPD-120 are connected to the main circuit board 130. Theinput pads IPD-120 are disposed in an input pad area IPP-120 which isdisposed at one side of the flexible wiring substrate 122. The input padarea IPP-120 may be disposed at the second side S2. In a plan view, theinput pad area IPP-120 overlaps the main circuit board 130.

The output pads OPD-120 are connected to the display panel 110. Theoutput pads OPD-120 may be disposed in an output pad area OPP-120 whichis disposed at the other side of the flexible wiring substrate 122. Theoutput pad area OPP-120 may be disposed at the first side S1. The outputpad area OPP-120 overlaps the display panel 110 in a plan view.

The input pads IPD-120 and the output pads OPD-120 may extend obliquelywith respect to the first direction A1 and the second direction A2,respectively. The input pads IPD-120 and the output pads OPD-120 may bearranged such that the input and output pads IPD-120 and OPD-120 on bothsides are symmetric to each other with respect to the center,respectively. The input pads IPD-120 and the output pads OPD-120according to an embodiment of the inventive concept may respectivelyextend in a direction in which the input pads IPD-120 and the outputpads OPD-120 converges toward at least one convergence point. A detaileddescription thereof will be described later.

In this embodiment, it is illustrated that one pad row is disposed ineach of the input pad area IPP-120 and the output pad area OPP-120. Thepad row includes a plurality of pads arranged along the second directionA2. However, the embodiment is merely exemplarily illustrated, so thatin an embodiment of the inventive concept, a plurality of pad rows mayalso be disposed in each of the input pad area IPP-120 and the outputpad area OPP-120, and the embodiment of the inventive concept is notlimited to any one embodiment.

The alignment pads APD-120 are disposed in the output pad area OPP-120.The alignment pads APD-120 are disposed adjacent to the output padsOPD-120. In this embodiment, the alignment pads APD-120 may be arrangedparallel to the output pads OPD-120. Accordingly, the alignment padsAPD-120 may extend in an oblique direction with respect to the firstdirection A1 and the second direction A2. However, the embodiment ismerely exemplarily illustrated, so that the alignment pads APD-120according to an embodiment of the inventive concept may be arranged invarious forms, and the embodiment of the inventive concept is notlimited to any one embodiment.

The alignment pads APD-120 may be a reference point for controlling theconnection position of the flexible circuit board 120 to the displaypanel 110 such that the flexible circuit board 120 is easily attached tothe display panel 110 without misalignment. In this embodiment, theflexible circuit board 120 may control a bonding position in the firstdirection A1 through the alignment pads APD-120.

The alignment mark AM-120 may be adjacent to a pad disposed in theoutermost side among the output pads OPD-120. The alignment mark AM-120may extend in a direction crossing the output pads OPD-120. In addition,the alignment mark AM-120 may be parallel to the direction in which thefirst side S1 of the flexible substrate 123 extends.

The alignment mark AM-120 may be a reference point for controlling theconnection position of the flexible circuit board 120 to the displaypanel 110 such that the flexible circuit board 120 is easily attached tothe display panel 110 without misalignment. In this embodiment, theflexible circuit board 120 may control the boding position in the seconddirection A2 through the alignment mark AM-120. A detailed descriptionthereof will be described later.

The stress relaxation pads SPD may be disposed between the alignmentpads APD-120 and the output pads OPD-120. The stress relaxation pads SPDmay be disposed on an empty space between the alignment pads APD-120 andthe output pads OPD-120.

The stress relaxation pads SPD are spaced apart from the alignment padsAPD-120 and the output pads OPD-120. The stress relaxation pads SPD areelectrically insulated from the output pads OPD-120.

The stress relaxation pads SPD fills the empty space disposed betweenthe alignment pads APD-120 and the output pads OPD-120. Accordingly, thestress relaxation pads SPD prevent an adhesive interconnect layer 140,which will be described later, from being filled in the empty spacedisposed between the alignment pads APD-120 and the output pads OPD-120.A detailed description thereof will be described later.

The alignment pads APD-120 and the output pads OPD-120 may be spacedfrom each other along the second direction A2 with the stress relaxationpads SPD interposed therebetween. In this embodiment, the number of thestress relaxation pads SPD provided herein may be two and the stressrelaxation pads SPD are spaced from each other along the seconddirection A2 with the output pads OPD-120 interposed therebetween.However, the embodiment is merely exemplarily illustrated, and thenumber of the stress relaxation pads SPD according to an embodiment ofthe inventive concept may be various numbers, and the stress relaxationpads SPD may be arranged asymmetrically to each other with respect tothe output pads OPD-120.

The stress relaxation pads SPD may have various shapes. In thisembodiment, the stress relaxation pads SPD are illustrated to have aparallelogram shape corresponding to the obliquely extending output padsOPD-120 and the obliquely extending alignment pads APD-120. However, theembodiment is merely exemplarily illustrated, so that the stressrelaxation pads SPD according to an embodiment of the inventive conceptmay have various shapes as long as being disposed in a space between thealignment pads APD-120 and the output pads OPD-120, and the embodimentof the inventive concept is not limited to any one embodiment.

Some of the wirings SL-120 are disposed at one side of the drivingcircuit 125, and the other parts of the wirings SL-120 are disposed atthe other side of the driving circuit 125. Some of the wirings SL-120connect the connection pads CPD and the input pads IPD-120.

The other part of the wirings SL-120 connect the connection pads CPD andthe output pads OPD-120. Although not illustrated, the wirings SL-120may also directly connect some of the input pads IPD-120 and some of theoutput pads OPD-120.

The flexible wiring substrate 122 may further include a solder resistlayer which is disposed on an insulation layer and covers at least thewirings SL-120. The solder resist layer may further cover the peripheryof the pads CPD, IPD-120, and OPD-120, but exposes each of the pads CPD,IPD-120, and OPD-120 at the least.

Openings corresponding to the pads CPD, IPD-120, and OPD-120 may beformed in the solder resist layer. The pads CPD, IPD-120, and OPD-120may be exposed from the solder resist layer and connected to the drivingcircuit 125, the main circuit board 130, and the display panel 110,respectively.

In this embodiment, the surface on which the pads CPD, IPD-120, OPD-120,and SPD are exposed may be defined as a coupling surface CS of theflexible wiring substrate 122, and the surface opposed to the couplingsurface CS may be defined as a non-coupling surface NCS. In thisembodiment, it is illustrated that the driving circuit 125 is mounted onthe coupling surface CS. However, the embodiment is merely exemplarilyillustrated, so that in an embodiment of the inventive concept, thedriving circuit 125 may be disposed on the non-coupling surface NCSdifferent from the surface on which the pads CPD, IPD-120, OPD-120, andSPD are exposed, and the embodiment of the inventive concept is notlimited to any one embodiment.

The driving circuit 125 may include at least one driving chip. In thisembodiment, the flexible circuit board 120 is illustrated to have achip-on-film structure, and the embodiment of the inventive concept isnot limited thereto.

The driving circuit 125 is electrically connected to the wirings SL-120on the flexible substrate 123. The driving circuit 125 may provideelectrical signals which drive the display panel 110 to the displaypanel 110. In addition, the driving circuit 125 may process electricalsignals output from the display panel 110 and provide the processedelectrical signals to the main circuit board 130.

The driving circuit 125 may be a various driving circuit. For example,the driving circuit 125 may include a data driving circuit 125. In thiscase, a pad part (not illustrated) of the display panel 110 includesdata pads electrically connected to data lines, and control signal padselectrically connected to control signal lines. The data lines may beconnected to the pixels PX, and the control signal lines may beconnected to a gate driving circuit.

However, such a configuration is merely exemplarily illustrated, so thatwhen the display panel 110 is a touch panel for sensing touch appliedfrom the outside, the driving circuit 125 may also provide a drivingsignal for sensing touch. The electronic device 100 according to anembodiment of the inventive concept may include various driving circuits125, and the embodiment of the inventive concept is not limited to anyone embodiment.

Referring again to FIG. 1 and FIG. 2 , the main circuit board 130 isconnected to the flexible circuit board 120. The main circuit board 130provides image data, a control signal, a power supply voltage, and thelike to the display panel 110 or the driving circuit 125. The maincircuit board 130 is a wiring substrate distinguished from the flexiblecircuit board 120, and may include an active element and a passiveelement. The main circuit board 130 may be flexible or rigid, and theembodiment of the inventive concept is not limited to any oneembodiment.

The electronic device 100 may further include an adhesive interconnectlayer 140, which is disposed between the main circuit board 130 and theflexible circuit board 120 to electrically connect the main circuitboard 130 and the flexible circuit board 120, and which is disposedbetween the display panel 110 and the flexible circuit board 120 toelectrically connect the display panel 110 and the flexible circuitboard 120.

The adhesive interconnect layer 140 has electrical conductivity and mayhave adhesiveness. The adhesive interconnect layer 140 may include athermosetting or photo-curable material. For example, the adhesiveinterconnect layer 140 may include an anisotropic conductive film (ACF).

The electronic device 100 according to an embodiment of the inventiveconcept includes electronic components, the display panel 110, theflexible circuit board 120, and the main circuit board 130 includingpads for electrical connection, and includes the adhesive interconnectlayer 140 for coupling the electronic components, the display panel 110,the flexible circuit board 120, and the main circuit board 130.Accordingly, the electronic device 100 may facilitate electricalconnection even for a plurality of electronic components independentlyprovided separately. A detailed description thereof will be describedlater.

FIG. 4 is a plan view in which the part of the electronic deviceillustrated in FIG. 1 is separated. FIG. 5A and FIG. 5B are plan viewsin which some of the elements illustrated in FIG. 4 are enlarged, andFIG. 5C is a plan view in which the elements illustrated in FIG. 4 arecoupled. Hereinafter, an electronic device according to an embodiment ofthe inventive concept will be described with reference to FIG. 4 to FIG.5C. The same elements as those described in FIG. 1 to FIG. 3C aredenoted by the same reference numerals, and redundant description willnot be provided herein.

As illustrated in FIG. 4 and FIG. 5A, the display panel 110 may includea plurality of input pads IPD-110 (hereinafter panel pads), a pluralityof alignment pads APD-110, and an alignment mark AM-110. The panel padsIPD-110, the alignment pads APD-110, and the alignment mark AM-110 aredisposed in the pad area PA.

The panel pads IPD-110 are connected to a plurality of signal linesSL-110. The panel pads IPD-110 may correspond to output pads OPD-120 ofthe flexible circuit board 120. The display panel 110 may beelectrically connected to the flexible circuit board 120 to receive datasignals, control signals, and the like.

Specifically, the panel pads IPD-110 are arranged along the seconddirection A2, and each may extend obliquely with respect to the firstdirection A1 and the second direction A2. Accordingly, the panel padsIPD-110 may form a first angle θ110 with respect to the first directionA1. The first angle θ110 is an acute angle, and may be greater than 0degrees and smaller than 90 degrees.

The panel pads IPD-110 may extend in oblique directions such that theleft-side pads and the right-side pads are symmetrical to each other.The left-side pads of the panel pads IPD-110 may extend in an obliquedirection such that the left-side pads are inclined to the right withrespect to the first direction A1, while the right-side pads of thepanel pads IPD-110 may extend in an oblique direction such that theright-side pads are inclined to the left with respect to the firstdirection A1.

The panel pads IPD-110 may each have a parallelogram shape having afirst length PDL-110. The panel pads IPD-110 may be arranged to bespaced apart from each other by a first interval PT-110 along the seconddirection A2. The first interval PT-110 may be constant or different foreach pad. For example, the first interval PT-110 may become greater asthe panel pads IPD-110 are farther away from the center toward theleft/right side.

The alignment pads APD-110 (hereinafter panel alignment pads) maycorrespond to the alignment pads APD-120 of the flexible circuit board120 in the alignment process for the flexible circuit board 120.Together with the alignment pads APD-120, the panel alignment padsAPD-110 may be used to control the position for connecting the flexiblecircuit board 120.

The panel alignment pads APD-110 are spaced apart from the panel padsIPD-110 along the second direction A2. A spaced space having a firstdistance WD-110 which is measured in the second direction A2 may beprovided between the panel alignment pads APD-110 and panel padsIPD-110. The first distance WD-110 may be defined as a distance betweena pad closest to the panel pads IPD-110 among the panel alignment padsAPD-110 and a pad closest to the panel alignment pads APD-110 among thepanel pads IPD-110.

The panel alignment pads APD-110 may have a shorter length than thepanel pads IPD-110. Accordingly, the panel alignment pads APD-110 mayhave parallelogram shapes having a second length APL-110 which isshorter than the first length PDL-110.

Meanwhile, in this embodiment, the panel alignment pads APD-110 areillustrated as a plurality of pads, but the embodiment is merelyexemplarily illustrated. Alternatively, the panel alignment pads APD-110according to an embodiment of the inventive concept may be a single pad,and the embodiment of the inventive concept is not limited to any oneembodiment.

The alignment mark AM-110 (hereinafter a panel alignment mark) may bespaced along the first direction A1 from the panel alignment padsAPD-110. The panel alignment mark AM-110 may correspond to the alignmentmark AM-120 of the flexible circuit board 120 in the alignment processfor the flexible circuit board 120.

The panel alignment mark AM-110 is disposed adjacent to the panel padsIPD-110. The panel alignment mark AM-110 may be disposed so as tocontact a pad IPD-E disposed in the outermost side among the panel padsIPD-110. However, the embodiment is merely exemplarily illustrated, sothat the panel alignment mark AM-110 may be provided in various forms aslong as the panel alignment mark AM-110 is able to correspond to thealignment mark AM-120 of the flexible circuit board 120, and theembodiment of the inventive concept is not limited to any oneembodiment.

Referring to FIG. 4 and FIG. 5B, the flexible circuit board 120 includesa plurality of output pads OPD-120, a plurality of alignment padsAPD-120, alignment marks AM-120, and a stress relaxation pad SPD.Meanwhile, the plurality of output pads OPD-120, the plurality ofalignment pads APD-120, the alignment marks AM-120, and the stressrelaxation pad SPD, illustrated in FIG. 5B are disposed substantially onthe rear surface, but are illustrated as being on the top surface byprojecting onto the top surface for easy explanation.

The output pads OPD-120 are arranged along the second direction A2, andeach extends obliquely with respect to the first direction A1 and thesecond direction A2. The output pads OPD-120 may extend in a directionforming a second angle θ120 with respect to the first direction A1.

The second angle θ120 may be the same or different for each of theoutput pads OPD-120. For example, the second angle θ120 may becomegreater as the output pads OPD-120 get closer to the left side or theright side from the center.

The output pads OPD-120 may be spaced by second intervals PT-120 withrespect to the second direction A2. The second intervals PT-120 may bethe same or different. In this embodiment, the second intervals PT-120are illustrated to be equal to each other. However, the embodiment ismerely exemplarily illustrated, and the second interval PT-120 maybecome greater or smaller as the output pads OPD-120 get closer to theleft side or the right side from the center.

The output pads OPD-120 may have parallelogram shapes having a thirdlength PDL-120 in the first direction A1. The third length PDL-120 maybe the same as or different from the first length PDL-110.

The alignment pads APD-120 are spaced from the output pads OPD-120 inthe second direction A2. The alignment pads APD-120 may have a shapesimilar to those of the output pads OPD-120. For example, the alignmentpads APD-120 may extend in a direction parallel to the output padsOPD-120.

The alignment pads APD-120 have a fourth length APL-120 in the firstdirection A1. The fourth length APL-120 may be smaller than the thirdlength PDL-120. In addition, the fourth length APL-120 may be largerthan the second length APL-110.

In this embodiment, the flexible circuit board 120 may aligned in amanner of considering the overlapping area of the alignment pads APD-120and the panel alignment pads APD-110. However, the embodiment is merelyexemplarily illustrated, so that the alignment pads APD-120 may alsohave a length equal to or less than the second length APL-110, and theembodiment of the inventive concept is not limited to any oneembodiment.

The alignment mark AM-120 is spaced apart from the alignment padsAPD-120 in the first direction A1. The alignment mark AM-120 may bealigned to the panel alignment mark AM-110 in the alignment process forthe flexible circuit board 120.

The stress relaxation pads SPD may be disposed in a space between thealignment pads APD-120 and the output pads OPD-120. Accordingly, asecond distance WD-120 between a pad OPD-E disposed at the outermostside among the output pads OPD-120 and a pad (herein, stress relaxationpad SPD) adjacent thereto is shorter than the first distance WD-110 inthe display panel 110.

The stress relaxation pads SPD may be pads independent from the outputpads OPD-120, the alignment pads APD-120, and the alignment mark AM-120.In a plan view, the stress relaxation pad SPD doesn't overlap the outputpads OPD-120, the alignment pads APD-120, and the alignment mark AM-120.The stress relaxation pads SPD may be electrically insulated from theoutput pads OPD-120.

Referring to FIG. 4 and FIG. 5C, the flexible circuit board 120 iscoupled to the display panel 110 with the adhesive interconnect layer140 interposed therebetween. In this case, the output pads OPD-120 ofthe flexible circuit board 120 and the panel pads IPD-110 of the displaypanel 110 respectively overlap and are electrically connected to eachother such that the flexible circuit board 120 and the display panel 110may be electrically connected.

In this case, the alignment pads APD-120 and the panel alignment padsAPD-110 may be used to determine whether the flexible circuit board 120is aligned in the first direction A1. For example, the position in thefirst direction A1 of the flexible circuit board 120 may be aligned suchthat the ends of the shaded panel alignment pads APD-110 are positionedin the middle of the alignment pads APD-120.

Meanwhile, the alignment mark AM-120 and the panel alignment mark AM-110may be used to determine whether the flexible circuit board 120 isaligned in the second direction A2. For example, the position in thesecond direction A2 of the flexible circuit board 120 may be alignedsuch that the protruding portion of the shaded panel alignment markAM-110 and the concave portion of the alignment mark AM-120 arepositioned to be aligned along the first direction A1. However, theembodiment is merely exemplarily illustrated, so that the electronicdevice according to an embodiment of the inventive concept may bealigned according to various alignment methods and may include variousalignment marks and alignment pads, and the embodiment of the inventiveconcept is not limited to any one embodiment.

The panel pads IPD-110 and the output pads OPD-120 overlap each otherand may thus be stably connected. In this embodiment, the panel padsIPD-110 and the plurality of output pads OPD-120 are illustrated to havea one to one correspondence, but are not limited thereto. In theelectronic device according to an embodiment of the inventive concept,the panel pads IPD-110 and the plurality of output pads OPD-120 mayinclude different number of pads or different number of pad rows, andthe embodiment of the inventive concept is not limited to any oneembodiment.

In this case, the stress relaxation pad SPD doesn't overlap any pad inthe display panel 110. As the flexible circuit board 120 and the displaypanel 110 are connected, the stress relaxation pad SPD may be disposedin a space between the panel pads IPD-110 and the panel alignment padsAPD-110. The stress relaxation pad SPD may have a width smaller than thefirst distance WD-110. Accordingly, the stress relaxation pad SPDdoesn't overlap the panel pads IPD-110 and panel alignment pads APD-110in a plan view.

The stress relaxation pad SPD according to an embodiment of theinventive concept may be an independent pad which is distinguished fromthe alignment pad and alignment mark for aligning the position betweenthe flexible circuit board 120 and the display panel 110. In addition,the stress relaxation pad SPD may be an independent pad which iselectrically insulated and thus distinguished from the panel padsIPD-110 and the plurality of output pads OPD-120.

The electronic device according to an embodiment of the inventiveconcept further includes a stress relaxation pad distinguished from apad for electrical connection or a pad for alignment, thereby enablingto improve the reliability of the electronic device and to reducedefects and the like after the connection process of the flexiblecircuit board 120. A detailed description thereof will be describedlater.

FIG. 6A is a cross-sectional view in which a part of the electronicdevice according to an embodiment of the inventive concept is separated.FIG. 6B is a cross-sectional view taken along line II-II′ illustrated inFIG. 5C. FIG. 6C is a cross-sectional view illustrating a part of theelectronic device according to an embodiment of the inventive concept.FIG. 7A and FIG. 7B are cross-sectional views of a part of an electronicdevice according to a comparative example. FIG. 6C illustrates the areacorresponding to the area of FIG. 6B for easy explanation. FIG. 7A andFIG. 7B are respectively cross-sectional views taken at different timesin order to describe the change over time.

Hereinafter, the electronic device according to an embodiment of theinventive concept will be described with reference to FIG. 6A to FIG.7B. The same elements as those described in FIG. 1 to FIG. 5C aredenoted by the same reference numerals, and redundant description willnot be provided herein.

FIG. 6A illustrates the display area DA and the pad area PA of thedisplay panel 110, respectively. As illustrated in FIG. 6A, the displaypanel 110 may include a base substrate BS, a first insulation layer Ill,a second insulation layer IL2, a thin film transistor TR, a pixelelectrode PE, and a pad PD. The second insulation layer IL2 may includea first layer IL21 and a second layer IL22.

The base substrate BS has an insulation property. The base substrate BSmay include a silicon substrate, a glass substrate, a plastic substrate,or a flexible film.

The thin film transistor TR and the pixel electrode PE constitute apixel PX (see FIG. 1 ). The thin film transistor TR may correspond tothe driving element described above. The first insulation layer IL1 isdisposed between the thin film transistor TR and the pixel electrode PE.The pixel electrode PE may be electrically connected to the thin filmtransistor TR through a contact hole formed in the first insulationlayer ILL

The thin film transistor TR includes a semiconductor pattern SM, acontrol electrode CE, an input electrode IE, and an output electrode OE.In a plan view, the control electrode CE is superimposed on thesemiconductor pattern SM. The control electrode CE may be spaced apartfrom the semiconductor pattern SM with the first layer IL21 of thesecond insulation layer IL2 interposed therebetween. In this embodiment,the first layer IL21 may be a gate insulation layer.

The input electrode IE and the output electrode OE may be disposed onthe second layer IL22 of the second insulation layer IL2. The inputelectrode IE and the output electrode OE may be connected to thesemiconductor pattern SM through contact holes form in the first layerIL21 and the second layer IL22. The second layer IL22 may be disposedbetween the control electrode CE and the input electrode IE, and betweenthe control electrode CE and the output electrode OE. In thisembodiment, the second layer IL22 may be a passivation layer.

The pixel electrode PE is disposed on the first insulation layer ILL Thepixel electrode PE may be one electrode of the display panel describedabove. The pixel electrode PE may be one electrode of a liquid crystalcapacitor, or may be an anode electrode or cathode electrode of theorganic light emitting element.

The first insulation layer IL1 is disposed between the pixel electrodePE and the thin film transistor TR. The first insulation layer IL1 maycover the thin film transistor TR to provide a flat surface to the pixelelectrode PE.

The first insulation layer IL1 may include a material different from thesecond insulation layer IL2. Particularly, the first insulation layerIL1 may include a material different from that of the second layer IL22,which is in contact with the first insulation layer IL1, among thesecond insulation layer IL2. In this embodiment, the first insulationlayer IL1 may include an organic material, and the second layer IL22 mayinclude an inorganic material.

Meanwhile, the pad PD may be provided on the second insulation layerIL2. The first insulation layer IL1 may extend from the display area DAto cover even the pad area PA. The first insulation layer IL1 includesan opening IL1-OP for exposing the pad PD in the pad area PA.

The first insulation layer IL1 is provided on the second insulationlayer IL2 to expose at least a portion of the pad PD. The surface of thepad PD, which is exposed by the first insulation layer Ill, may be aconnection surface to which the external terminal is connected.Meanwhile, the first insulation layer IL1 may have a relatively smallerthickness in the pad area PA than in the display area DA. Therefore, athickness T1 in the pad area PA of the first insulation layer IL1 may beequal to or less than a thickness T2 in the display area DA. That is,the thickness T1 of the first insulation layer IL1 in the pad area PAmay be the same as the thickness T2 in the display area DA or smallerthan the thickness T2 in the display area DA. In the electronic deviceaccording to an embodiment of the inventive concept, the thickness ofthe first insulation layer IL1 in the pad area PA is relatively reducedto easily expose the connection surface of the pad PD, thereby achievingstable connection with the external terminal.

The display panel 110 may receive an electrical signal applied from theoutside through the connection surface of the pad PD, or may provide thegenerated electrical signal to the outside. In this embodiment, the padPD may be disposed on the same layer as the input electrode IE and theoutput electrode OE.

However, the embodiment is merely exemplarily illustrated, and the padPD may include a plurality of conductive patterns laminated along thethickness direction. In this case, the conductive patterns are disposedbetween the first layer IL21 and the base substrate BS and between thefirst layer IL21 and the second layer IL22, and may be connected to eachother through a contact hole formed in the second insulation layer IL2.Even in this case, the pad PD connected to the external terminal may beprovided on the second insulation layer IL2.

As illustrated in FIG. 6B, the display panel 110 includes a basesubstrate 110-BS, a first insulation layer 110-IL1, a second insulationlayer 110-IL2, and a plurality of pads in a cross sectional view. Inthis embodiment, the pads PD illustrated in FIG. 6A are exemplarilyillustrated as the panel pads IPD-110 and the panel alignment padsAPD-110.

The first insulation layer 110-IL1 and the second insulation layer110-IL2 may be some components of a driving element layer. The firstinsulation layer 110-IL1 may correspond to the first insulation layerIL1 illustrated in FIG. 6A, and the second insulation layer 110-IL2 maycorrespond to the second insulation layer IL2.

The first insulation layer 110-IL1 is disposed on the base substrate110-BS. Although not illustrated, at least one conductive layer may befurther disposed between the first insulation layer 110-IL1 and the basesubstrate 110-BS. The first insulation layer 110-IL1 may include anorganic material. In this embodiment, the thickness of the firstinsulation layer 110-IL1 may be about 8000 Å or less.

The second insulation layer 110-1L2 is disposed between the firstinsulation layer 110-IL1 and the base substrate 110-BS. Although notillustrated, at least one conductive layer may be further disposedbetween the second insulation layer 110-IL2 and the first insulationlayer 110-IL1.

The first insulation layer 110-IL1 is disposed on the second insulationlayer 110-IL2 to expose at least some of each of the panel pads IPD-110and the panel alignment pads APD-110. The exposed pads contact theadhesive interconnect layer 140.

The second insulation layer 110-IL2 may include a material differentfrom that of the first insulation layer 110-IL1. For example, the secondinsulation layer 110-IL2 may include an inorganic material. For example,the second insulation layer 110-IL2 may include silicon oxide, siliconnitride, or a combination thereof. Accordingly, the second insulationlayer 110-IL2 has a lower adhesive force with respect to the firstinsulation layer 110-IL1 than in the case where the second insulationlayer 110-IL2 includes the same material as the first insulation layer110-IL1 or includes an organic material.

The panel pads IPD-110 and the panel alignment pads APD-110 are disposedon the second insulation layer 110-IL2. In this embodiment, the panelpads IPD-110 and the panel alignment pads APD-110 may contact the firstinsulation layer 110-IL1.

The panel pads IPD-110 and the panel alignment pads APD-110 are disposedon the same layer. The panel pads IPD-110 and the panel alignment padsAPD-110 may include the same material, and may be patterned at the sametime by using a single mask.

The adhesive interconnect layer 140 may include a plurality ofconductive particles 141 and a resin layer 142. The conductive particles141 are dispersed in the resin layer 142.

The conductive particles 141 may include a material having highelectrical conductivity. In addition, the conductive particles 141 mayinclude a material having high malleability or high workability. Theconductive particles 141 are disposed between the panel pads IPD-110 andthe output pads OPD-120 to electrically connect the panel pads IPD-110and the output pads OPD-120.

The resin layer 142 allows the conductive particles 141 to be stablydispersed in a space defined by the first thickness DS1 between theflexible circuit board 120 and the display panel 110. The resin layer142 has adhesiveness. The resin layer 142 may include a thermosetting orphoto-curable material.

In this embodiment, the resin layer 142 may be in contact with the firstinsulation layer 110-IL1. Due to adhesiveness inherent in the resinlayer 142, an adhesive force acts between the resin layer 142 and thefirst insulation layer 110-IL1. In this embodiment, the adhesive forcebetween the resin layer 142 and the first insulation layer 110-IL1 maybe greater than the adhesive force between the first insulation layer110-IL1 and the second insulation layer 110-IL2.

The electronic device according to this embodiment further includes astress relaxation pad SPD. The stress relaxation pad SPD is disposed onthe same layer as the output pads OPD-120 and the alignment padsAPD-120. Therefore, the stress relaxation pad SPD may be disposed on asecond base substrate 120-BS which is a flexible wiring substrate 122 inFIG. 2 .

In this embodiment, the stress relaxation pad SPD may include the samematerial as the output pads OPD-120 and the alignment pads APD-120. Forexample, the stress relaxation pad SPD may include a metal having highconductivity. The stress relaxation pad SPD, the output pads OPD-120,and the alignment pads APD-120 may be patterned at the same time byusing a single mask. However, the embodiment is merely exemplarilyillustrated, so that the stress relaxation pad SPD may include amaterial different from those of the output pads OPD-120 and thealignment pads APD-120, and may also be formed by other processesdiffering from the processes for the output pads OPD-120 and thealignment pads APD-120.

The stress relaxation pad SPD is disposed not to overlap any other pads.However, the stress relaxation pad SPD is disposed so as to superimposethe space between the panel pads IPD-110 and the panel alignment padsAPD-110.

Accordingly, the first thickness DS1 of the adhesive interconnect layer140 is reduced to a second thickness DS2 by the stress relaxation padsSPD present in the empty space between the panel pads IPD-110 and thepanel alignment pads APD-110. The specific effects thereof will bedescribed in more detail with reference to the following comparativeexample.

FIG. 7A illustrates a comparative example 100-E1 in a state in which apressure is applied for coupling to the flexible circuit board 120, andFIG. 7B illustrates a comparative example 100-E2 after a predeterminedtime has passed. Here, the comparative examples 100-E1 and 100-E2 havethe same structure with each other but has only a time differencetherebetween. In addition, in the comparative examples 100-E1 and100-E2, all configurations except for the stress relaxation pad SPDcorrespond to the electronic device according to an embodiment of theinventive concept are the same, so that redundant description will notbe provided herein. In this embodiment, the coupling of the flexiblecircuit board and the display panel may be performed by athermo-compression bonding process.

As illustrated in FIG. 7A, when a predetermined pressure is applied inorder to couple a flexible circuit board 120 and a display panel 110, apredetermined compression stress PS may be applied to a second basesubstrate 120-BS_A. A plurality of pads PD_A1 and PD_A2 disposed on thelower surface of the second the base substrate 120-BS_A. And a pluralityof pads PD_A3 and PD_A4 disposed on the upper surface of the first basesubstrate 110-BS_A. The pads PD_A1, PD_A2, PD_A3, and PD_A4 arerespectively corresponding to pads OPD-120, APD-120, IPD-110, andAPD-110. An adhesive interconnect layer 140_A has flexibility andfluidity, so that the compression stress PS caused by pressure partiallyreduces the thickness of the adhesive interconnect layer 140_A disposedbetween the plurality of pads PD_A1 and PD_A2.

Then, as illustrated in FIG. 7B, when the predetermined pressure appliedto the flexible circuit board 120 and the display panel 110 is removed,a stress RS caused by a repulsive force may be applied to the secondbase substrate 120-BS_B. The stress RS caused by the repulsive force maycorrespond to tensile stress, and is applied in the upward directionopposite to the application direction of the compression stress PS,while having the same magnitude as that of the compression stress PS.

The stress RS caused by the repulsive force of the second base substrate120-BS_B may correspond to resilience, and thus the second basesubstrate 120-BS-B may be returned to a flat shape.

In this case, the adhesive interconnect layer 140_B may be also movedupward due to the stress RS caused by the repulsive force. However, theadhesive interconnect layer 140_B has been cured, and thus has lowerfluidity than the adhesive interconnect layer 140_A in FIG. 7A.Accordingly, the adhesive interconnect layer 140_B may not restore thereduced thickness but moves upward together with the second basesubstrate 120-BS_B by a movement force RS-d of the second base substrate120-BS_B.

In this case, a first insulation layer 110-IL1_B, which is in contactwith the adhesive interconnect layer 140_B, is lifted upward from asecond insulation layer 110-IL2_B. Accordingly, a predetermined space SPis formed between the second insulation layer 110-IL2_B and the firstinsulation layer 110-IL1_B, and a gap GP is formed due to the lifting.

According to the comparative example, the adhesive force between thesecond insulation layer 110-IL2_B and the first insulation layer110-IL1_B, which is made of a material different from that of the secondinsulation layer 110-IL2_B, fails to overcome the movement force RS-dapplied to the first insulation layer 110-IL1_B, thereby causingdelamination defects.

Alternatively, the electronic device according to an embodiment of theinventive concept further includes a stress relaxation pad SPD, therebyreducing the thickness of the adhesive interconnect layer 140 in theregion where the area contacting the first insulation layer 110-IL1 islarge. Thus, even when the second base substrate 120-BS is restoredafter being deformed, the change in thickness of the adhesiveinterconnect layer 140 is reduced, so that the influence on the firstinsulation layer 110-IL1 may be reduced. Therefore, the electronicdevice according to the embodiment of the inventive concept furtherincludes the stress relaxation pad SPD, thereby easily solving thedelamination in the display panel 110 and improving the reliability ofthe electronic device.

Meanwhile, as illustrated in FIG. 6C, an electronic device 100-S mayfurther include a solder resist layer SRP. The solder resist layer SRPis disposed on the second base substrate 120-BS which is a flexiblewiring substrate 122 in FIG. 2 to expose the output pads OPD-120,alignment pads APD-120, and stress relaxation pad SPD of the flexiblecircuit board 120. Although not illustrated, the circuit wiringsconnected to the output pads OPD-120 may be covered by the solder resistlayer SRP. Thus, it is possible to prevent a short circuit caused by theadhesive interconnect layer 140, and to stably protect the circuitwirings, thereby improving the reliability of the electronic device100-S.

FIG. 8A illustrates a first alignment state of an electronic deviceaccording to an embodiment of the inventive concept, and FIG. 8Billustrates a second alignment state of the electronic deviceillustrated in FIG. 8A. FIG. 9A illustrates a third alignment state ofan electronic device according to a comparative example, and FIG. 9Billustrates a fourth alignment state of an electronic device accordingto a comparative example.

FIG. 8A and FIG. 8B illustrate only some of panel pads PD1 and outputpads PD2 for easy explanation, and FIG. 9A and FIG. 9B illustrate onlysome of comparison panel pads PD1-E and comparison output pads PD2-E soas to correspond to those in FIG. 8A and FIG. 8B, respectively.

The comparative panel pads PD1-E and the comparative output pads PD2-Ein the comparative examples EX-A1 and EX-A2 illustrated FIG. 9A and FIG.9B may correspond to the panel pads PD1 and the output pads PD2illustrated in FIG. 8A and FIG. 8B, except for having a shape extendingin a parallel direction rather than in an oblique direction with respectto the first direction A1. Hereinafter, the electronic device accordingto an embodiment of the inventive concept will be described withreference to FIG. 8A to FIG. 9B.

In an electronic device 100-A1 in a first alignment state illustrated inFIG. 8A, some of the pads may be in a misalignment state. When the firstalignment state is a process state in which the panel pads PD1 spaced bythe first interval DT1 and the output pads PD2 spaced by a secondinterval DT2 different from the first interval DT1 are aligned, it isillustrated that certain panel pads PD1-M among the panel pads PD1 andcertain output pads PD2-M among the output pads PD2 are not superimposedin a plan view.

Even when considering that the certain panel pads PD1-M and the certainoutput pads PD2-M are spaced apart from or brought into simple contactwith each other, the resistance between the certain panel pads PD1-M andthe certain output pads PD2-M is very large, so that the certain panelpads PD1-M and the certain output pads PD2-M may be substantiallyrecognized as being in a misalignment state in which electricalconnection is not achieved.

The second alignment state of the electronic device 100-A2 illustratedin FIG. 8B may be a process state in which the misalignment state of theelectronic device 100-A1 in the first alignment state illustrated inFIG. 8A is corrected. When the output pads PD2 are moved in a directionparallel to the first direction A1 along the arrow direction, thecertain panel pads PD1-M and the certain output pads PD2-M misalignedwith each other in FIG. 8A may overlap each other. Accordingly, all padsof the electronic device 100-A2 in the second alignment state may berecognized as being in the alignment state in which all the pads areconnected to each other.

Referring to FIG. 9A and FIG. 9B, when the third alignment state of thecomparative example EX-A1 is a process state in which the panel padsPD1-E spaced by the first interval PT1-E and the output pads PD2-Espaced by the second interval PT2-E different from the first intervalPT1-E are aligned, certain panel pads PD1-E_M1 and certain output padsPD2-E_M1 may appear as being in a misalignment state in which thecertain panel pads PD1-E_M1 and the certain output pads PD2-E_M1 are notconnected to each other.

Hereafter, the comparative example EX-A2 in a fourth alignment statewill be described with reference to FIG. 9B. Even when the certain panelpads PD1-E_M1 and the certain output pads PD2-E_M1 are moved along thearrow direction from the third alignment state in the comparativeexample EX-A1 for electrical connection, other panel pads PD1-E_M2 andother output pads PD2-E_M2 may happen to be in a new misalignment state.

The panel pads PD1-E and the output pads PD2-E according to thecomparative example have a shape extending in a parallel directionrather than in an oblique direction to the first direction A1, so thatthe movement in the first direction A1 has no influence on whether thepanel pads PD1-E and the output pads PD2-E are connected to each other.In addition, the movement in the second direction A2 in a state in whicheach of the intervals between the panel pads PD1-E and the output padsPD2-E is fixed may cause new connection failures.

The electronic device according to an embodiment of the inventiveconcept includes the panel pads extending in an oblique direction,thereby enabling to more easily control the alignment process betweenthe circuit board and the display panel, and to improve the badconnection problem. In particular, when the intervals between the panelpads and the output pads are different from each other, for example,even when a output pad interval changes due to a process error ordeformation of a circuit board caused by heat in the thermo-compressionbonding process, the existing connection process may be maintainedwithout change, thereby reducing process costs and simplifying theprocess.

In addition, the electronic device according to an embodiment of theinventive concept includes a stress relaxation pad and alignment padscorresponding to output pads, so that even when pads are further added,influences such as the interference with the output pads and the panelpads may be reduced, and an easy design is possible.

FIG. 10 is a plan view illustrating output pads according to anembodiment of the inventive concept. As illustrated in FIG. 10 , theoutput pads OPD-110_1 may include pads having different tilt angles.

FIG. 10 exemplarily illustrates a first pad OPD-110_C, a second padOPD-110_M, and a third pad OPD-110_P.

The first pad OPD-110_C may be a pad disposed at the center. In thisembodiment, the first pad OPD-110_C may be a pad disposed at a middlewhich is the center of the output pads OPD-110_1.

The first pad OPD-110_C may have a shape extending along the firstdirection A1. The pads arranged on the left side of the first padOPD-110_C and the pads arranged on the right side of the first padOPD-110_C may be arranged so that there is one line of symmetry. A linepassing through a center of the first pad OPD-110_C may be a line ofsymmetry.

The second pad OPD-110_M may be disposed adjacent to the first padOPD-110_C. The second pad OPD-110_M may extend in a direction inclinedat a first angle θ110_C with respect to the second direction A2.

The third pad OPD-110_P may be disposed in the outermost side of theoutput pads OPD-110_1. The third pad OPD-110_P may extend in a directioninclined at a second angle θ110_P with respect to the second directionA2.

In this embodiment, as the output pads OPD-110_1 get closer to theoutside from the center, that is, the farther away from the center alongthe second direction A2, the output pads OPD-110_1 may extend in anoblique direction inclined at a smaller angle with respect to the seconddirection A2. Accordingly, the second angle θ110_P may be smaller thanthe first angle θ110_C.

In this embodiment, the output pads OPD-110_1 may not be parallel toeach other. Thus, the extended imaginary lines of the respective outputpads OPD-110_1 may converge toward at least one convergence point.

The electronic device according to an embodiment of the inventiveconcept may include panel pads or output pads having various shapes andarrangements as along as the pads extend in an oblique direction withrespect to the first direction A1 and the second direction A2, and theembodiment of the inventive concept is not limited to any oneembodiment.

FIG. 11A is a plan view in which a part of an electronic deviceaccording to an embodiment of the inventive concept is separated, andFIG. 11B is a plan view illustrating a part of an electronic deviceaccording to an embodiment of the inventive concept, and FIG. 11C is across-sectional view taken along line III-III′ illustrated in FIG. 11B.FIG. 11A exemplarily illustrates a part of the flexible circuit board120-1 among the elements of the electronic device. Hereinafter, theelectronic device according to an embodiment of the inventive conceptwill be described with reference to FIG. 11A to FIG. 11C. The sameelements as those described in FIG. 1 to FIG. 10 will be denoted by thesame numerals, and redundant description will not be provided herein.

As described in FIG. 11A, the electronic device may include a flexiblecircuit board 120-1 including a stress relaxation pad SPD-1. The stressrelaxation pad SPD-1 may include a plurality of sub-pads.

In this embodiment, the sub-pads are exemplarily illustrated as first tothird sub-pads SPD1, SPD2, and SPD3. The first to third sub-pads SPD1,SPD2, and SPD3 may be arranged apart from each other along the seconddirection A2.

In a plan view, the first to third sub-pads SPD1, SPD2, and SPD3 arespaced apart from the alignment pads APD-120_1 and the output padsOPD-120. The first to third sub-pads SPD1, SPD2, and SPD3 areillustrated to be spaced apart from the output pads OPD-120 by thesecond distance WD-120 in the second direction A2.

All of the first to third sub-pads SPD1, SPD2, and SPD3 are disposed ina space between the alignment pads APD-120_1 and the output pads OPD-120which are spaced apart from each other. The widths or the intervals ofthe first to third sub-pads SPD1, SPD2, and SPD3 may be the same ordifferent. In this embodiment, the first to third sub-pads SPD1, SPD2,and SPD3 are illustrated to have the same pitch PT-SPD1, but theembodiment is merely exemplarily illustrated, so that the first to thirdsub-pads SPD1, SPD2, and SPD3 may be arranged in various forms as longas being disposed in a space between the alignment pads APD-120_1 andthe output pads OPD-120 which are spaced apart from each other.

The first to third sub-pads SPD1, SPD2, and SPD3 are disposed in a spacebetween the alignment mark AM-120, the output pads OPD-120, and thealignment pads APD-120_1. Thus, the total width in the second directionA2 occupied by the first to third sub-pads SPD1, SPD2, and SPD3 may beequal to or less than a spaced distance between the alignment padsAPD-120_1 and the output pads OPD-120 in the second direction A2.

The lengths of the first to third sub-pads SPD1, SPD2, and SPD3 in thefirst direction A1 may be limited to the length which allows the firstto third sub-pads SPD1, SPD2, and SPD3 not to overlap the alignment markAM-120. In particular, the length of the first to third sub-pads SPD1,SPD2, and SPD3 in the first direction A1 may be limited to the lengthwhich allows the first to third sub-pads SPD1, SPD2, and SPD3 not tooverlap the panel alignment mark AM-110 in a plan view. In thisembodiment, the length LH of each of the first to third sub-pads SPD1,SPD2, and SPD3 in the first direction A1 is larger than the lengthAPL-120 of the alignment pads APD-120_1 in the first direction A1, andis smaller than the length PDL-110 of the output pads OPD-120 in thefirst direction A1.

The first to third sub-pads SPD1, SPD2, and SPD3 may have shapescorresponding to the adjacent pads. The first to third sub-pads SPD1,SPD2, and SPD3 may have a shape corresponding to at least any one of thealignment pads APD-120_1 and the output pads OPD-120. In thisembodiment, the first to third sub-pads SPD1, SPD2, and SPD3 areexemplarily illustrated to have a shape and an arrangement similar tothose of the alignment pads APD-120_1.

Hereafter, as illustrated in FIG. 11B and FIG. 11C, the flexible circuitboard 120-1 is coupled to the display panel 110 through an arrangementstep and a thermo-compression bonding step which are not illustrated.The output pads OPD-120 and the panel pads IPD-110 overlap each other ina plan view, and electrically connected through the adhesiveinterconnect layer 140.

The alignment pads APD-120_1 and the panel alignment pads APD-110 mayoverlap each other in a plan view to be aligned each other. In thisembodiment, the alignment pads APD-120_1 may have the same lengthAPL-120 as the panel alignment pads APD-110 in the first direction A1.

Accordingly, in the electronic device in which the flexible circuitboard 120-1 and the display panel 110 are coupled, the alignment padsAPD-120_1 may be illustrated to be completely overlap panel alignmentpads APD-110 in a plan view. However, the embodiment is merelyexemplarily illustrated, so that the alignment of the flexible circuitboard 120-1 and the display panel 110 according to an embodiment of theinventive concept may be performed through various methods, and theembodiment of the inventive concept is not limited to any oneembodiment.

In a plan view, the stress relaxation pad SPD-1 doesn't overlap anyother pads. Thus, the first to third sub-pads SPD1, SPD2, and SPD3 mayface the underlying second insulation layer 110-IL2 with the adhesiveinterconnect layer 140 interposed therebetween. The adhesiveinterconnect layer 140 may have a reduced thickness DS2 in the area inwhich the adhesive interconnect layer 140 overlap the first to thirdsub-pads SPD1, SPD2, and SPD3 in a plan view.

Referring to FIG. 11B, when connecting the flexible circuit board 120-1and the display panel 110, a portion of the adhesive interconnect layer140 disposed in a stress concentration area AA′ surrounded by the panelalignment mark AM-110, the output pads OPD-120, and the stressrelaxation pad SPD-1 may move between the first to third sub-pads SPD1,SPD2, and SPD3. Accordingly, the movement FLD of the adhesiveinterconnect layer 140 may occur between the first to third sub-padsSPD1, SPD2, and SPD3.

In this embodiment, since the stress concentration area AA′ issurrounded by the panel alignment mark AM-110, the output pads OPD-120,and the stress relaxation pads SPD-1, the movement of the adhesiveinterconnect layer 140 may be occurred.

The electronic device 100-1 according to an embodiment of the inventiveconcept includes a stress relaxation pad SPD-1 including the first tothird sub-pads SPD1, SPD2, and SPD3, thereby facilitating the movementof the adhesive interconnect layer 140 disposed in the stressconcentration area AA′. Accordingly, delamination defects between theoutput pads OPD-120 and the alignment pads APD-120 may be reduced, andthe biasing phenomenon of the adhesive interconnect layer 140 which mayoccur in the stress concentration area AA′ may be also improved.

FIG. 12 is a plan view illustrating a part of the electronic deviceaccording to an embodiment of the inventive concept. FIG. 13A is across-sectional view taken along line IV-IV′ illustrated in FIG. 12 .FIG. 13B is a cross-sectional view illustrating a part of the electronicdevice according to an embodiment of the inventive concept. FIG. 12illustrates a part of the flexible circuit board 120-2. FIG. 13Aillustrates a part of the electronic device which includes the flexiblecircuit board 120-2 illustrated in FIG. 12 , and corresponds to an areataken along line IV-IV′. FIG. 13B illustrates a partial area thatcorresponds to FIG. 13A and is of an electronic device according to anembodiment of the inventive concept. Hereinafter, the flexible circuitboard 120-2 according to an embodiment of the inventive concept will bedescribed with reference to FIG. 12 . The same elements as thosedescribed in FIG. 1 to FIG. 11C will be denoted by the same numerals,and redundant description will not be provided herein.

As illustrated in FIG. 12 , the flexible circuit board 120-2 may includea stress relaxation pad SPD-2 and an alignment pad APD-120_2 which aredifferent from those of the flexible circuit board 120-1. The stressrelaxation pad SPD-2 is exemplarily illustrated to have three sub-padsSPD4, SPD5, and SPD6. The sub-pads SPD4, SPD5, and SPD6 may be forth tosixth sub-pads SPD4, SPD5, and SPD6.

The forth to sixth sub-pads SPD4, SPD5, and SPD6 may have shapesdifferent from each other. For example, the forth to sixth sub-padsSPD4, SPD5, and SPD6 may have different lengths in the first directionA1.

Among the forth to sixth sub-pads SPD4, SPD5, and SPD6, the fifth andsixth sub-pads SPD5 and SPD6, which are adjacent to the output padsOPD-120, have a shape relatively similar to those of the output padsOPD-120, and, among the forth to sixth sub-pads SPD4, SPD5, and SPD6,the fourth sub-pad SPD4 adjacent to the alignment pads APD-120_2 mayhave a shape relatively similar to those of the alignment padsAPD-120_2.

Accordingly, it may be illustrated that the fifth and sixth sub-padsSPD5 and SPD6 have a length similar to the length PDL-110 in the firstdirection A1 of the output pad OPD-120, and the fourth sub-pad SPD4 hasa smaller length than the length PDL-110. However, the embodiment ismerely exemplarily illustrated, so that the fourth to sixth sub-padsSPD4, SPD5, and SPD6 may have various shapes, and the embodiment of theinventive concept is not limited to any one embodiment.

The alignment pads APD-120_2 may include first alignment pads APD1 andsecond alignment pads APD2. The first alignment pads APD1 maysubstantially correspond to the alignment pads APD-120_1 illustrated inFIG. 11A.

The second alignment pads APD2 are disposed adjacent to the firstalignment pad APD1 in the second direction A2. The second alignment padsAPD2 are illustrated to have a shape similar to the first alignment padsAPD1. In this case, the second alignment pads APD2 may utilize the samedesign dimension as the first alignment pads APD1, so that the processmay be simplified. However, the embodiment is merely exemplarilyillustrated, so that the second alignment pads APD2 according to anembodiment of the inventive concept may have a shape different from thefirst alignment pads APD1, and the embodiment of the inventive conceptis not limited to any one embodiment.

The second alignment pads APD2 may be disposed in the outside of an edgeline EDL disposed between the first alignment pads APD1 and the secondalignment pads APD2. The second alignment pads APD2 may reduce thealignment error of the flexible circuit board 120-2 to improve thepreciseness in the connection process of the flexible circuit board120-2. In addition, the second alignment pads APD2 may alleviate thelifting phenomenon of a second insulation layer 110-IL2 (see FIG. 11C),which may occur outside the edge line EDL.

Meanwhile, the flexible circuit board 120-2 according to an embodimentof the inventive concept may further include an additional stressrelaxation pad SPD-3. The additional stress relaxation pad SPD-3 may bedisposed outside the alignment mark AM-120. The additional stressrelaxation pad SPD-3 is disposed outside the edge line EDL.

Referring to FIG. 13A, the additional stress relaxation pad SPD-3doesn't overlap any other panel pads. The additional stress relaxationpad SPD-3 may directly face the first insulation layer 110-IL1 with theadhesive interconnect layer 140 interposed therebetween. The flexiblecircuit board 120-2 according to an embodiment of the inventive conceptmay further include a second alignment pads APD2 and an additionalstress relaxation pad SPD-3, thereby easily preventing delaminationbetween the first insulation layer 110-IL1 and the second insulationlayer 110-IL2, which may occur in the end regions of the output pads.

Referring to FIG. 13B, the electronic device may include a window padWPD disposed on the base substrate 110-BS. In this case, a portion ofthe first insulation layer 110-IL1 overlapping the window pad WPD may beremoved. Accordingly, the window pad WPD is disposed on the secondinsulation layer 110-IL2.

The window pad WPD may include a metal. For example, the window WPD padmay be formed of the same material as the panel pads (not illustrated).

The window pad WPD may be disposed so as to overlap an additional stressrelaxation pad SPD-3_A. The additional stress relaxation pad SPD-3_A mayface the window pad WPD with the adhesive interconnect layer 140disposed therebetween.

At least a portion of the conductive particles 141 in the adhesiveinterconnect layer 140 is disposed between the window pad WPD and theadditional stress relaxation pad SPD-3_A, and thus may be compressed bythe window pad WPD and the additional stress relaxation pad SPD-3_A.According to an embodiment of the inventive concept, it is possible toeasily check whether the electrical connection is stably achievedbetween the panel pads and the output pads by means of the window padWPD and the additional stress relaxation pad SPD-3_A.

In an embodiment of the inventive concept, a delamination phenomenonthat may occur due to the difference in resilience between theelectronic components after electrically connecting the electroniccomponents by using the thermo-compression bonding may be alleviated.Further, since a pad structure capable of stably achieving theelectrical connection is provided even when the electronic components orthe like are deformed due to the thermo-compression bonding, aconnection failure caused by the alignment error in the bonding processmay be prevented.

Although the exemplary embodiments of the present inventive concept havebeen described, it is understood that the present inventive conceptshould not be limited to these exemplary embodiments but various changesand modifications can be made by one ordinary skilled in the art withinthe spirit and scope of the present inventive concept as hereinafterclaimed.

Therefore, the technical scope of the present inventive concept shouldnot be limited to the contents described in the detailed description ofthe specification, but should be defined by the claims.

What is claimed is:
 1. An electronic device comprising: a display panelincluding a display area, a peripheral area, and a pad area in a planview, the display panel comprising: a plurality of pixels disposed inthe display area, and a plurality of panel pads disposed in the padarea, the plurality of panel pads being spaced apart in a firstdirection from the plurality of pixels and each of the plurality ofpanel pads being arranged along a second direction crossing the firstdirection; a circuit board, the circuit board comprising: a plurality ofoutput pads which are connected to the plurality of panel pads,respectively, and an alignment pad spaced apart from the plurality ofoutput pads along the second direction; and a first pad spaced apart inthe second direction from the plurality of output pads in a plan viewand electrically insulated from the plurality of panel pads.
 2. Theelectronic device of claim 1, wherein the plurality of output pads havepredetermined extension angles with respect to the first direction andat least two pads among the plurality of output pads have differentextension angles.
 3. The electronic device of claim 1, wherein intervalsof the plurality of panel pads become greater as distances from a centerof the pad area increase.
 4. The electronic device of claim 1, whereinintervals of the plurality of output pads are different according todistances from a center of the pad area.
 5. The electronic device ofclaim 1, wherein the first pad is disposed between the plurality ofoutput pads and the alignment pad in a plan view.
 6. The electronicdevice of claim 1, wherein each of the plurality of output pads extendsobliquely with respect to the first direction and the second direction,and the plurality of output pads are arranged along the seconddirection.
 7. The electronic device of claim 1, wherein a length of thefirst pad in the first direction is greater than or equal to a length ofthe alignment pad in the first direction and is less than or equal tolengths of the plurality of output pads in the first direction.
 8. Theelectronic device of claim 7, wherein the display panel furthercomprises an additional alignment pad disposed on a base substrate onwhich the plurality of panel pads are disposed and spaced apart from thealignment pad in the first direction, and wherein the first pad isspaced apart from the alignment pad, the output pad, and the additionalalignment pad in a plan view.
 9. The electronic device of claim 1,wherein the plurality of output pads overlap the plurality of panel padsin a plan view and the first pad is spaced apart from the plurality ofpanel pads in a plan view.
 10. The electronic device of claim 9, furthercomprising an adhesive interconnect layer disposed between the displaypanel and the circuit board, and electrically connecting the displaypanel and the circuit board.
 11. The electronic device of claim 10,wherein the plurality of panel pads are disposed between a basesubstrate and a first insulation layer, and wherein the adhesiveinterconnect layer is in contact with the first insulation layer in anarea in which the adhesive interconnect layer is superimposed on thefirst pad.
 12. The electronic device of claim 11, wherein at least aportion of the plurality of panel pads are partially exposed by thefirst insulation layer, and wherein the adhesive interconnect layercomprises: an adhesive layer, and a plurality of conductive particlesdispersed in the adhesive layer, and wherein the adhesive layer and thefirst insulation layer are in contact with each other in an area inwhich the adhesive interconnect layer is superimposed on the first pad.13. The electronic device of claim 11, further comprising a secondinsulation layer disposed between the first insulation layer and thebase substrate, wherein an adhesive force between the first insulationlayer and the adhesive interconnect layer is greater than an adhesiveforce between the first insulation layer and the second insulationlayer.
 14. The electronic device of claim 1, wherein the first pad isdisposed on a flexible substrate.
 15. The electronic device of claim 14,wherein the display panel further comprises a second pad spaced apartfrom the plurality of panel pads and overlap the first pad in a planview.
 16. The electronic device of claim 15, wherein the plurality ofpanel pads are disposed between a base substrate and a first insulationlayer, and wherein a portion of the first insulation layer overlappingthe second pad is removed.
 17. The electronic device of claim 1, furthercomprising alignment mark which is spaced apart in the first directionand electrically insulated from the plurality of panel pads.
 18. Theelectronic device of claim 17, wherein the alignment mark is connectedto a pad disposed in the outermost side among the plurality of outputpads.
 19. The electronic device of claim 17, wherein the first padcomprises a plurality of sub-pads which are spaced apart from each otheralong the second direction.
 20. The electronic device of claim 19,wherein the sub-pads extend in a direction crossing the plurality ofoutput pads.
 21. The electronic device of claim 19, wherein the sub-padsextend in a direction parallel to the plurality of output pads.
 22. Theelectronic device of claim 21, wherein the sub-pads extend in adirection parallel to the output pad closest to the sub-pads among theplurality of output pads.
 23. The electronic device of claim 19, whereina length of the sub-pads in the first direction allows the sub-pads notto overlap the alignment mark.
 24. The electronic device of claim 23,wherein the length of the sub-pads in the first direction is larger thana length of the alignment pad in the first direction and the length ofthe sub-pads in the first direction is smaller than each length of theplurality of output pads in the first direction.
 25. The electronicdevice of claim 24, wherein the sub-pads comprises a first sub-paddisposed adjacent to the alignment pad, a second sub-pad, and a thirdsub-pad disposed adjacent to the plurality of output pads, the secondsub-pad being disposed between the first sub-pad and the second sub-pad,and wherein a shape of the first sub-pad is different from shapes of thesecond pad and the third sub-pad.
 26. The electronic device of claim 25,wherein the shape of the first sub-pad is similar to a shape of thealignment pads.
 27. The electronic device of claim 25, wherein a lengthof the second sub-pad and a length of the third sub-pad are similar to alength of the plurality of output pads, and wherein a length of thefirst sub-pad is smaller than the length of the second sub-pad and thethird sub-pad.